Cyclopropenoid fatty acids (CPFA) which occur in certain foodstuffs such as cottonseed oil and flour, kapok oil and okra are known to have toxic effects when consumed by animals. These unique compounds are known to impair reproduction in rats and chickens, alter the fatty acid composition in the body lipids of several species, and cause characteristic alterations in trout and rabbit liver parenchymal cells. In addition, our studies have demonstrated that CPFA act as powerful cocarcinogens with aflatoxin B1 and as carcinogens in the induction of liver cancer in rainbow trout. The goal of this research is to provide understanding and insight into the mechanisms of induction and promotion of cancer and concomitant physiological effects seen with dietary CPFA. A thorough understanding of these mechanisms will help to explain the different species responses to CPFA and will provide information relative to their potential health hazard to man. C14-sterculic acid will be administered to trout and rats. The metabolites from their liver lipids, and from trout gall bladder, will be separated, isolated and the structures determined. Similarily, the metabolites will be separated from the liver protein fraction and identified. The toxicity of the major urinary metabolite will be determined. An analytical method for the quantitative detection of CPFA in the parts per million range will be developed.